User:Chibill/Map Format

Rewrite in progress This article is currently being rewriten for Minecraft 1.13 Format.

This page covers the world information as of 17w47a to the present. See Alpha Map Format for Alpha information. See [[..]] for Information before the "Flattening". Though some information is also valid for before 17w47a.

General Information

Worlds are represented as a series of regions, within which are a number of columns, and chunks. Each region is 32x1x32 columns, each column is 1x16x1 chunks, and each chunk is 16x16x16 blocks. The overall block height of a column is 256. Each chunk stores four (or five) things - block state array (Long Array), block light (4-bit),palette, and sky light (4-bit).Block light is light cast by things like torches and glowstone, and is calculated with a 3D Flood Fill algorithm. Sky light is the light cast by the sky, and is calculated by starting at the top and working your way down. As you pass through semi-transparent blocks, you decrease the lighting value until you hit an opaque block. The opaque block is the last block whose skylight has a nonzero value. Lighting starts at 0xF (brightest) and works down to 0x0 (dimmest). Columns store biome information. Each 1x256x1 cuboid of blocks has the same biome value, for a total of 256 possible biome values per chunk (16x16). Biome values are stored as bytes.

Biome Values

Name	Value
Ocean	0
Plains	1
Desert	2
Extreme Hills	3
Forest	4
Taiga	5
Swampland	6
River	7
Hell	8
Sky	9
Frozen Ocean	10
Frozen River	11
Ice Plains	12
Ice Mountains	13
Mushroom Island	14
Mushroom Island Shore	15
Beaches	16
Desert Hills	17
Forest Hills	18
Taiga Hills	19
Extreme Hills Edge	20
Jungle	21
Jungle Hills	22
Jungle Edge	23
Deep Ocean	24
Stone Beach	25
Cold Beach	26
Birch Forest	27
Birch Forest Hills	28
Roofed Forest	29
Cold Taiga	30
Cold Taiga Hills	31
Mega Taiga	32
Mega Taiga Hills	33
Extreme Hills+	34
Savanna	35
Savanna Plateau	36
Mesa	37
Mesa Plateau F	38
Mesa Plateau	39
The Void	127
Sunflower Plains	129
Desert M	130
Extreme Hills M	131
Flower Forest	132
Taiga M	133
Swampland M	134
Ice Plains Spikes	140
Jungle M	149
JungleEdge M	151
Birch Forest M	155
Birch Forest Hills M	156
Roofed Forest M	157
Cold Taiga M	158
Mega Spruce Tagia	160
Redwood Taiga Hills M	161
Extreme Hills+ M	162
Savanna M	163
Savanna Plateau M	164
Mesa (Bryce)	165
Mese Plateau F M	166
Mesa Plateau M	167

Storage

This section documents the Anvil format for servers.

Maps are stored as a specific directory structure with several NBT files within. For the sake of examples, the world we'll be working with is stored in a folder called "/world".

Directory Structure

• /world/data: Stores extra world data (Villages,Mineshafts,Temples)
• /world/DIM-1: Nether world
• /world/DIM-1/region: Nether world regions
• /world/DIM1: End world
• /world/DIM1/region: End world regions
• /world/players: Player data
• /world/region: Overworld regions

level.dat

In the root directory is a level.dat file. The structure of that file is this:

• NBTCompound(Data)
  • NBTCompound(DataPacks)
    • NBTList(Disabled)
    • NBTList(Enabled): Generally contains the string "vanilla"
  • NBTCompound(DimensionData)
    • NBTCompound(1)
      • NBTCompound(DragonFight)
        • NBTList(Gateways)
        • NBTByte(DragonKilled)
        • NBTByte(PreviouslyKilled)
  • NBTCompound(GameRules)
    • NBTString(announceAdvancemtns): One for each game rule with the value being the game rules value.
  • NBTCompound(Version)
    • NBTInt(Id): 1451 for 17w47a
    • NBTString(Name): Name of the version
    • NBTByte(Snapshot): If the version is a snapshot
  • NBTDouble(BoarderCenterX)
  • NBTDouble(BoarderCenterZ)
  • NBTDouble(BoarderDamagerPerBlock)
  • NBTDouble(BorderSafeZone)
  • NBTDouble(BoarderSize)
  • NBTDouble(BorderSizeLerpTarget)
  • NBTLong(BorderSizeLerpTime)
  • NBTDouble(BoarderWarningBlocks)
  • NBTDouble(BoarderWarningTime)
  • NBTInt(clearWeatherTime)
  • NBTInt(DataVersion)
  • NBTLong(DayTime)
  • NBTByte(Difficulty)
  • NBTByte(DifficultyLocked)
  • NBTInt(GameType)
  • NBTString(generatorName)
  • NBTString(generatorOptions)
  • NBTInt(generatorVersion)
  • NBTByte(hardcore)
  • NBTByte(initialized)
  • NBTLong(LastPlayed)
  • NBTString(LevelName)
  • NBTByte(MapFeatures): Set to 1 if structures are generated, such as villages
  • NBTByte(raining): Set to 1 if currently raining
  • NBTInt(rainTime): The ticks remaining until rain stops?
  • NBTLong(RandomSeed)
  • NBTLong(SizeOnDisk): Has been 0 since 1.2.5 (Weird? Whats the point of this?)
  • NBTInt(SpawnX)
  • NBTInt(SpawnY)
  • NBTInt(SpawnZ)
  • NBTByte(thundering): Set to 1 if currently thundering (only if there is potential for thunder, not if a thunderbolt is currently in progress)
  • NBTInt(thunderTime)
  • NBTInt(version)

[playeruuid].dat

Each player that has ever connected is given a [playeruuid].dat file.

• NBTCompound
  • NBTCompound(abilities)
    • NBTByte(flying): 1 if flying
    • NBTFloat(flySpeed): Generally 0.05
    • NBTByte(instaBuild)
    • NBTByte(invulnerable)
    • NBTByte(mayBuild)
    • NBTByte(mayFly)
    • NBTFloat(walkSpeed): Generally 0.1
  • NBTCompound(recipeBook)
    • NBTList(recipes)
    • NBTList(toBeDisplayed)
    • NBTByte(isFilteringCraftable)
    • NBTByte(isGuiOpen)
  • NBTCompound(Attributes)
    • NBTCompound(): One entry for each Attribute the player has.
      • NBTDouble(Base)
      • NBTString(Name)
  • NBTList(EnderItems)
  • NBTCompound(Inventory)
    • NBTCompound
      • NBTCompound(tag)
        • NBTInt(Damage)
      • NBTByte(Count)
      • NBTByte(Slot)
      • NBTString(id)
  • NBTList(Motion)
    • NBTDouble
    • NBTDouble
    • NBTDouble
  • NBTList(Pos)
    • NBTDouble
    • NBTDouble
    • NBTDouble
  • NBTList(Rotation)
    • NBTFloat
    • NBTFloat
  • NBTFloat(AbsorptionAmount)
  • NBTShort(Air)
  • NBTInt(DataVersion)
  • NBTShort(DeathTime)
  • NBTInt(Dimension)
  • NBTFloat(FallDistance)
  • NBTByte(FallFlying)
  • NBTShort(Fire): Ticks until the player is no longer on fire, or zero
  • NBTFloat(foodExhaustionLevel)
  • NBTInt(foodLevel)
  • NBTFloat(foodSaturationLevel)
  • NBTInt(foodTickTimer)
  • NBTShort(Health)
  • NBTInt(HurtByTimestamp)
  • NBTShort(HurtTime)
  • NBTByte(Invnerable)
  • NBTByte(OnGround)
  • NBTInt(playerGameType)
  • NBTInt(PortalCooldown)
  • NBTInt(Score)
  • NBTByte(seenCredits)
  • NBTInt(SelectedItemSlot)
  • NBTByte(Sleeping)
  • NBTShort(SleepTimer)
  • NBTLong(UUIDLeast)
  • NBTLong(UUIDMost)
  • NBTInt(XpLevel)
  • NBTFloat(XpP)
  • NBTFloat(XpSeed)
  • NBTInt(XpTotal)

[region].mca

Each region file is named "r.x.z.mca", where x and z are the coordinates. These coordinates are relative to each region. Given column coordinates, divide them by 32 to get the region coordinates.

• NBTCompound
  • NBTCompound(Chunk [x,z]): x and z are region column coordinates, not relative to the overall world. The compound name is a misnomer, it actually represents column.
    • NBTCompound(Level)
      • NBTByte(TerrainPopulated): 1 if this column has been generated
      • NBTInt(xPos): In global, world-relative chunk coordinates
      • NBTInt(zPos): In global, world-relative chunk coordinates
      • NBTLong(LastUpdate): The last time a block changed in this column
      • NBTByte(LightPopulated)
      • NBTByte(TerrainPopulated)
      • NBTLong(InhabitedTime)
      • NBTByteArray(Biomes): Always 256 Entries
      • NBTList(Entities)
        • NBTCompound
          • NBTByte(OnGround)
          • NBTShort(Air)
          • NBTShort(AttackTime)
          • NBTShort(DeathTime)
          • NBTShort(Fire)
          • NBTShort(Health)
          • NBTShort(HurtTime)
          • NBTFloat(FallDistance)
          • NBTString(id): Example: "Skeleton"
          • NBTList(Motion)
            • NBTDouble
            • NBTDouble
            • NBTDouble
        • NBTList(Pos)
          • • NBTDouble
            • NBTDouble
            • NBTDouble
        • NBTList(Rotation)
          • NBTFloat
          • NBTFloat
      • NBTList(Sections): Chunks
        • NBTCompound
          • NBTByte(Y): 0-16
          • NBTByteArray(BlockLight)
          • NBTLongArray(BlockStates)
          • NBTList(Palette): Holds the palette for the blocks stored in the NBTLongArray. They are stored much in the same way as in the Chunk Data Packet. See Chunk_Format#Chunk_Section_structure
            • NBTCompound()
              • NBTString(Name)
            • NBTCompound()
              • NBTString(Name)
              • NBTCompound(Properties)
                • NBTString(<name>) : Key is the name of the property being saved
          • NBTByteArray(SkyLight)
      • NBTList(TileEntities)
      • NBTIntArray(HeightMap): 256 entries